The present invention relates to a module such as a high-frequency module for a small sized electronic apparatus such as a mobile telephone, a method of manufacturing the module, and particularly to a signal electrode provided on a printed circuit board for the high-frequency module.
A conventional high-frequency module includes a substrate of substantially a four-sided shape having a recess provided in each cut side thereof, an electronic component mounted on the substrate, and a signal electrode provided at the recesses. One end of the signal electrode is exposed at the cut sides.
The substrate is manufactured in the following manner. As shown in FIG. 18, a printed mother board 2 incorporates an array of substrates 1 for high-frequency modules. As shown in FIG. 19, each of the substrates 1 has a pattern of a signal electrode 3 provided at all lateral sides thereof where neighboring substrates 1 are linked. Also, a signal electrode 4 is provided at each corner of each substrate 1. The signal electrodes 3 and 4 are formed by forming holes and coating the holes with copper plating so as to allow the holes to function as through holes. The printed mother board 2 is then cut along a joint 5 to provide the substrates 1.
Because of having copper plated signal electrodes 3 and 4 cut along the joint 5, each conventional high-frequency module may have burrs developed at its edges. The burrs decline quality of the plating of each signal electrode. More specifically, when the module is mounted in a circuit assembly, the burrs possibly are detached by adverse vibrations, thus causing a short-circuit. Hence, the burrs need to be removed during an extra process step performed by a worker.
A module includes a substantially four-sided substrate having a recess formed at a lateral side thereof, an electrode provided at the recess of the substrate, an absent portion between lateral sides of the substrate, and an electronic component mounted on the substrate. The module has the electrode without unwanted burrs.